1.1 --- a/src/share/vm/gc_implementation/g1/vm_operations_g1.cpp Mon Jun 28 14:13:18 2010 -0400
1.2 +++ b/src/share/vm/gc_implementation/g1/vm_operations_g1.cpp Mon Jun 28 14:13:17 2010 -0400
1.3 @@ -42,8 +42,65 @@
1.4 void VM_G1IncCollectionPause::doit() {
1.5 JvmtiGCForAllocationMarker jgcm;
1.6 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1.7 + assert(!_should_initiate_conc_mark ||
1.8 + ((_gc_cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
1.9 + (_gc_cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)),
1.10 + "only a GC locker or a System.gc() induced GC should start a cycle");
1.11 +
1.12 GCCauseSetter x(g1h, _gc_cause);
1.13 - g1h->do_collection_pause_at_safepoint();
1.14 + if (_should_initiate_conc_mark) {
1.15 + // It's safer to read full_collections_completed() here, given
1.16 + // that noone else will be updating it concurrently. Since we'll
1.17 + // only need it if we're initiating a marking cycle, no point in
1.18 + // setting it earlier.
1.19 + _full_collections_completed_before = g1h->full_collections_completed();
1.20 +
1.21 + // At this point we are supposed to start a concurrent cycle. We
1.22 + // will do so if one is not already in progress.
1.23 + bool res = g1h->g1_policy()->force_initial_mark_if_outside_cycle();
1.24 + }
1.25 + g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
1.26 +}
1.27 +
1.28 +void VM_G1IncCollectionPause::doit_epilogue() {
1.29 + VM_GC_Operation::doit_epilogue();
1.30 +
1.31 + // If the pause was initiated by a System.gc() and
1.32 + // +ExplicitGCInvokesConcurrent, we have to wait here for the cycle
1.33 + // that just started (or maybe one that was already in progress) to
1.34 + // finish.
1.35 + if (_gc_cause == GCCause::_java_lang_system_gc &&
1.36 + _should_initiate_conc_mark) {
1.37 + assert(ExplicitGCInvokesConcurrent,
1.38 + "the only way to be here is if ExplicitGCInvokesConcurrent is set");
1.39 +
1.40 + G1CollectedHeap* g1h = G1CollectedHeap::heap();
1.41 +
1.42 + // In the doit() method we saved g1h->full_collections_completed()
1.43 + // in the _full_collections_completed_before field. We have to
1.44 + // wait until we observe that g1h->full_collections_completed()
1.45 + // has increased by at least one. This can happen if a) we started
1.46 + // a cycle and it completes, b) a cycle already in progress
1.47 + // completes, or c) a Full GC happens.
1.48 +
1.49 + // If the condition has already been reached, there's no point in
1.50 + // actually taking the lock and doing the wait.
1.51 + if (g1h->full_collections_completed() <=
1.52 + _full_collections_completed_before) {
1.53 + // The following is largely copied from CMS
1.54 +
1.55 + Thread* thr = Thread::current();
1.56 + assert(thr->is_Java_thread(), "invariant");
1.57 + JavaThread* jt = (JavaThread*)thr;
1.58 + ThreadToNativeFromVM native(jt);
1.59 +
1.60 + MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
1.61 + while (g1h->full_collections_completed() <=
1.62 + _full_collections_completed_before) {
1.63 + FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
1.64 + }
1.65 + }
1.66 + }
1.67 }
1.68
1.69 void VM_CGC_Operation::doit() {
